In recent years, owing to rapid development of computer graphic rendering technologies, these technologies have found wide application in various fields such as in the silver spoon industry, the video games industry, and the like. However, due to limitation of hardware, a high-resolution signal often has to be represented at a low resolution in the computer graphic rendering technologies, and even sometimes positional coordinates of a graphic cannot be calculated accurately. This leads to occurrence of serrations at edges of objects in the display frame, which is known as the “aliasing” phenomenon.
Referring to FIG. 1A, a schematic view illustrating the aliasing phenomenon is shown therein. In FIG. 1A, a display frame 10 comprises sixteen pixels, each of which is represented by a square. The triangle 102 is a virtual area (virtual region), which represents an image to be presented in the display frame 10. When the sampling rate is one sampling point (in FIG. 1A, the black dot in each square represents a sampling point) per pixel, the pixel can only be updated with a color and a luminance sampled at the sampling point. When this sampling rate is used to sample the triangle 102 and sample values are used to update pixels of the display frame 10, a frame displayed in FIG. 1A will be presented, where the gray squares represents the triangle 102. As can be seen from FIG. 1A, this sampling rate causes occurrence of the aliasing phenomenon.
Increasing the sampling rate is known as a technical means to alleviate the aliasing phenomenon, and schematic views of this concept are shown in FIGS. 1B, 1C, 1D, and 1E. FIG. 1B depicts a scenario where the sampling rate is sixteen sampling points per pixel, and FIG. 1C depicts a scenario where the sampling rate is four sampling points per pixel. Although increasing the sampling rate may mitigate the aliasing phenomenon, it also increases the volume of data to be stored and computed. In order to ease the burden imposed by the increased sampling rate on the system, a technology of sharing sampling points has been developed, which is schematically shown in FIG. 1D and FIG. 1E. In FIG. 1D, the sampling rate is five sampling points per pixel. Because four of the sampling points are located at corners of this pixel, data corresponding to the four sampling points may also be used for adjacent pixels. In FIG. 1E, the sampling rate is four sampling points per pixel, and data corresponding to the four sampling points may also be used for adjacent pixels. Although the technical means of increasing the sampling rate shown in FIG. 1D and FIG. 1E reduces the volume of data to be stored and computed significantly, quality of the resulting frames still cannot fulfill the requirements in practical use.
Accordingly, a need still exists in the art for a graphic rendering system and a pixel update method thereof that can fulfill the requirements on display quality by solving the aliasing problem and, meanwhile, eliminate the need of storing and processing a large volume of data.